After eating lettuce contaminated with ehec (e. coli) , what physical/chemical barriers to infection will the pathogen encounter en route to the intestine and once it reaches the intestine, but before it can attach to epithelial cells of the intestine?
choose all the correct options below: a. defensinsb. cytolytic t-cellsc. activated macrophagesd. perforinse. lysozymef. mucing. stomach acidh. iggi. gut microbiotaj. tight junctions of gastrointestinal epithelial layers

Defensins, lysozymes, mucin, stomach acid, gut microbiota, tight junctions of gastrointenstinal epithelial cells are the physical/chemical barriers to infection will the pathogen encounter en route to the intestine and once it reaches the intestine after eating lettuce contaminated with EHEC

Explanation:

The enterohemorrhagic strain of Escherichia coli (EHEC) grows in the intestines, produces the highly potent Shiga toxin. E.coli is a foodborne pathogen.  

Innate immunity acts against the EHEC pathogens through physical and chemical barriers with certain non-specific responses.

Physical barriers include skin and mucous membrane. Chemical barriers include stomach acid, lysozyme, defensin.

Tight junctions are the watertight regions lining the gastrointestinal mucosal surface with tightly packed epithelial cells which prevent the flow of E. coli bacteria between the host compartments.

The mucous membranes covered with tight junctions secrete mucin and lysozyme.

Mucin blocks the pathogen’s ability to attach to the cell surfaces and thereby inhibits its invasion.  

Lysozymes are mucosal enzymes which act against the pathogens trying to adhere to the gut epithelium.

Defensins are peptides that attack the cytoplasmic membrane of the pathogens and kill them

Stomach acid (HCl) reduces the pH of the gut and maintains an acidic environment, and thereby inhibits the entry of foodborne pathogens

Gut microbes are commensal organisms that aid immunity by:

a polymer is a chainlike molecule made up of small molecular units. these small molecular units are called monomers. monomers of polymer can be joined together either naturally or synthetically.  

videntify the dna change shown in the diagram and explain how that change can result in the increased genetic diversity often seen among siblings.identify the dna change shown in the diagram and explain how that change can result in the increased genetic diversity often seen among siblings.